One improved form of manually operable tube bender is disclosed in U.S. Pat. No. 3,685,335 of Leonard J. Kowal. As shown thereimn, a mandrel is provided with a peripheral arcuate groove into which a tube to be bent is urged by a cooperating shoe. The shoe is swingably mounted in association with the mandrel and is moved by means of a handle extending outwardly therefrom. The mandrel, in turn, is supported on a second handle rigidly connected thereto, and in the tube forming operation, the first handle is brought from a start position wherein it extends generally perpendicularly to the second handle to a final position wherein the grasping portion thereof is disposed adjacent the grasping portion of the second handle.
It is desirable to limit the swing of the first handle so as to avoid a crossover between the handles in effecting the desired bend. Such limitation restricts the amount of movement of the shoe about the mandrel groove. It has been proposed to incorporate, in the tube bender, means for permitting the first handle to be repositioned from the initial end position adjacent the grasping portion of the first handle so as to permit a further travel of the bending shoe about the mandrel by effecting a subsequent movement of the first handle similarly to the initial movement thereof between the bend start location and the position adjacent the second handle grasping means. Thus, a bend of up to 180.degree. may be effected with such structure without losing the desirable leverage and thereby permitting the bending of relatively rigid tubing.
U.S. Pat. No. 2,979,976 and 3,190,105 attempt to provide this feature in the prior art. The benders disclosed in these patents, however, suffer from the problems of being complex in design and thus more expensive to manufacture. Further, U.S. Pat. No. 2,979,976 discloses a manual locking mechanism which is cumbersome to use while U.S. Pat. No. 3,190,105 discloses a bender design in which the operation of repositioning the handle requires more care and control.